I think the best books are non-fiction, about 200 pages and fairly non-technical (ie not grad school textbooks.)
The sort of thing that might be easy to use the system on would be an easy self help book like the natural brilliance one in the study course.
The easy books I've photoread have been on: - NLP books. - "Natural born winners"- Robin Sieger - French women don't get fat. - Lance Armstrong - Every second counts
I recommend to learn it... no "learning" is in case of PR a false word. I would rather say "make sure" that it works on self-development books.
It's necessary to have an interest in it. If you do it on books you aren't curious about and/or don't really want to know about, it'd be harder to learn anything from them.